How to set it up:
Run /give @p diamond_sword{ench:[{id:100,lvl:1}]}
Place an anvil
Get a sword enchantment book (sharpness for example)
Place Diamond Sword in first slot on anvil, and then sharpness book in second slot. (Game Should Crash)
MC-128296
Game Crash While Using Unreal Enchantment ID & Real Enchantment ID inside Avnvil
Resolved
Duplicate
0
Duplicated by https://bugs.mojang.com/browse/MC-113127 didn't see this until just after I posted. Sorry =|